Conventionally, there is known a travel control technology such as ACC (Adaptive Cruise Control: constant speed traveling/inter-vehicular distance control device) and a PCS (Pre-Crash Safety System), which performs travel control of a vehicle by using detection results obtained by a radar device.
The travel control technology is constituted to restrict or prohibit the travel control of a vehicle according to a determination result of axis deviation occurring in the radar device, such that a failure does not occur when axis deviation occurs in the radar device.